The migratory plant-parasitic nematode is the pathogen of the pine wilt disease (PWD), causing serious damage to pine forests in China. During the process of plant resistance to multiple pathogens, plant immunity plays a key role. In this current study, the pathogen-associated molecular pattern (PAMP) BxCDP1 in has been identified, but the host target protein of BxCDP1 and its key amino acid region inducing the plant immunity have yet to be elucidated. We found that BxCDP1 could trigger superoxide production, HO production, and callose deposits. A RING-H2 finger protein 1 (RHF1) of was screened and characterized as a target protein of BxCDP1 by yeast two-hybrid and co-immunoprecipitation (Co-IP). Moreover, two peptides (namely M9 and M16) proved to be key regions of BxCDP1 to induce PAMP-triggered immunity (PTI) in , which also induced the expression of pathogenesis-related (PR) genes (, , and ) in and enhanced the resistance of the host to . These results indicate that BxCDP1 plays a critical role in the interaction between and , and both peptides M9 and M16 have the potential to be developed and utilized as immune inducers of pines against in future.